<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>演示：边框、尺寸</title>

        <style type="text/css">

            #mydiv{
                width: 70px;
                height: 70px;
                border: 1px solid black;
            }


        </style>
    </head>
    <body>
        <!--需求：给页面某个div设置：宽度200像素，高度200像素，1像素实线黑色的框-->
        <div id="mydiv">传智播客</div>
        
    </body>
</html>